Recent discoveries in nanofiber technologies open up new avenues for the fabrication of high-area permeable supports from conductive polymers and carbon nanotubes. Nanofibrous supports (NFS) with designed hierarchical pore structure architecture can provide a unique environment for biosensing due to controlled fluid delivery and retention and ability to facilitate direct electron transfer. This interdisciplinary collaborative R21 proposal aims at the development of novel NFSs for biosensor packaging and design of NFS-based biosensor nanofluidic systems. We will modify the existing methods of fabrication of nanoporous fibers and webs to produce electro-conductive and hydrodynamically tunable supports for biosensors. The project exploits the advantages of two recently proposed nanofiber technologies: particle coagulation spinning and electrospinning. Three types of NFSs will be studied to test their applicability for biosensor packaging: nanoporous fibers made of single wall carbon nanotubes by PCS process, electrospun nanowebs made of conductive polymer nanofibers, and polymer nanofiber/carbon nanotube composite webs. We will explore different NFS-based electrochemical biosensor formats and their potential as integrated components in micro-Total Analytical Systems. The main attention will be paid on i) direct electron transfer sensor catalyzed by enzymes that are caged in NFS and ii) electrochemical immunosensors ELISA improved by NFS transducers. The proposed project will be performed at the Center for Modeling and Characterization of Nanoporotm Materials at TRl/Princeton under direction of Dr. Neimark (expertise in nanofibrous materials and fluid flow) in collaboration with Prof. Atanassov, Department of Chemical and Nuclear Engineering at the University of New Mexico (expertise in electrochemical biosensing). We will cooperate also with Dr. Schreuder-Gibson, US Army Soldier Biological & Chemical Command, Natick Soldier Center (expertise in electrospinning of conductive polymers and carbon nanotube composite webs) and Dr. Poulin, CNRS, Bordeaux, France (expertise in synthesis of carbon nanotube fibers). Within the proposed program we will i) synthesize NFS in the form of nanoporous fibers and webs and study their chemical, mechanical, and transport properties in biochemical environments ii) assess the performance of NFS in bench-top model bioanalytical systems, iii) develop processing methods to integrate NFS into a wide array of cutting-edge bioanalytical device architectures. We anticipate that the techniques to be developed from the proposed R21 project will have a groundbreaking impact on biosensor engineering. In the short- term, our research program will yield a new class of biomaterials tbr the next generation of biomedical sensors, which would employ NFS as electrochemical transducers. In the long-term, we will elaborate a strategy to design carbon/polymeric nanocomposites with desired functionalities, which will have a broad impact on engineering of novel building blocks for nanofluidic machinery for various biomedical applications.